The invention relates to a device for automatic stacking of package on a support in a predetermined spatial arrangement to form a stack. Automatic stacking onto a support or a carrier, in particular a pallet or a trolley, with package to form a stack for later shipment, i.e. “palletization”, is known per se. However, in this respect, packages of uniform size or dimension are placed by robots, grabs, etc., at arithmetically determined sites. In contrast, the process of automatically loading a load support with packages with different specifications to form a stack is so-called “mixed-case” palletization. In current distribution logistics, ever greater demands are placed on picking. Picking systems, therefore, need to be developed which process orders automatically without manual intervention.
Thousands of different products (or package) of the most varied possible specifications (size, shape, weight, dimensions, surfaces, solidity, etc.) must be picked automatically by such systems.
In this case, it is necessary to consider many aspects which greatly increase complexity compared with the “simple” manual stacking of simple, regular geometries. Thus, a package can be properly stacked or placed on a preceding package only when this has a flat or even surface, which should also be oriented approximately horizontally, and when the package can bear the weight of the further package placed on it without being damaged. Furthermore, the stack formed should have a certain stability in order that, amongst other things, it does not fall over during transportation. Wrapping with film does help, but cannot stabilize an incorrectly formed stack alone. In addition, it is more often the case that the recipient desires the stacks to be optimized with a view to the desired unloading sequence.
Stacking of different packages or goods of different sizes or dimensions is, therefore, still mainly carried out by hand since the requirements of stack stability, packing density within the stack and the loading sequence, as well as the unloading sequence dictated thereby, and not least the stackability of the goods are extremely high and thus far also only partially met by the known methods and devices.
EP 1 462 394 B1 discloses a device for automatic loading of a load support with packing units forming a load stack, i.e., a palletizing device. With this device, the packing units are supplied individually and on boards and are placed therefrom onto a packing table. At that location, the packing unit is displaced, lying on the table, by a pusher along the broad side of the pallet to be loaded until the loading coordinates in the X direction are reached. Then, a further pusher and a loading tongue simultaneously push the packing unit in the direction of the load depth over the pallet until the loading coordinates in the Z direction are reached. Then, the loading tongue returns, wherein the pusher remains stationary and serves as a stripper so that the packing unit is set down on the pallet at the desired location in a “free-fall” manner. The stack being formed is supported by a loading aid on the remaining three sides. It is virtually a case of “against the wall” stacking. However, the displacement on the packing table is time-consuming and, owing to limited accessibility, is disadvantageous for formation of the packing patterns. In addition, it is necessary for the loading tongue and the stripper/pusher to travel simultaneously in the X direction. Moreover, only one packing unit can ever be “processed” at a time.
WO 2010/059923 A1 discloses an automatic robot-assisted stacking device in which an intermediate plate for formation of the first layer of a stack and simultaneous pallet change is used.